Okinawa Institute of Science and Technology Graduate University, Onna, Okinawa 904-0495, Japan.
School of Engineering, University of Liverpool, Brownlow Street, Liverpool L69 3GH, United Kingdom.
Phys Rev E. 2016 Mar;93(3):031101. doi: 10.1103/PhysRevE.93.031101. Epub 2016 Mar 9.
We examine fluid flow through cross-slot devices with various depth to width ratios α. At low Reynolds number, Re, flow is symmetric and a sharp boundary exists between the two incoming fluid streams. Above an α-dependent critical value, Re(c)(α), a steady symmetry-breaking bifurcation occurs and a spiral vortex structure develops. Order parameters characterizing the instability grow according to a sixth-order Landau potential, and show a progression from second- to first-order transitions as α increases beyond a tricritical value of α ≈ 0.55. Flow simulations indicate the instability is driven by vortex stretching at the stagnation point.
我们研究了具有不同深度与宽度比α的十字缝装置中的流体流动。在低雷诺数 Re 下，流动是对称的，两个流入流体流之间存在明显的边界。高于依赖于α的临界值 Re(c)(α)时，会发生稳定的对称破缺分岔，并且会形成螺旋涡旋结构。特征失稳的序参量根据六阶朗道势增长，并且随着α超过约 0.55 的三临界点增加，表现出从二阶到一阶的转变。流动模拟表明，不稳定性是由驻点处的涡拉伸驱动的。
